$A$ man of mass $m_1$ is standing at a height $h$ from the floor in a gravity-free room. He throws a ball of mass $m_2$ downwards with a speed $u$. Find the distance of the man from the floor when the ball reaches the floor.

• A
  $\left( \frac{m_2}{m_1} \right) h$
• B
  $\left( 1 - \frac{m_2}{m_1} \right) h$
• C
  $\left( 1 + \frac{m_2}{m_1} \right) h$
• D
  $\left( 1 - \frac{m_2}{m_1} \right)^2 h$